1. Field of the Invention
This invention relates to billing for communications usage. In particular it relates to a billing system responsive to usage events in a communications network to process event data to support invoice production.
2. Related Art
In communications networks such as public switched telecommunications networks (PSTN), the customer receives charges based on usage of the network. Hence a billing system needs to detect usage of the network and to process data in respect of that usage so as to output a bill or other charging mechanism.
For instance, when telephone calls are established across the British PSTN, records are created at the exchanges recording details about the call. The details will include information such as duration of the call, time of day of the call, start and end, the originating telephone line and destination telephone line. This information is periodically accessed by billing systems and processed into invoices which are sent out to the customer.
A problem with present billing systems is that they can be very inflexible. For instance, when a communications service provider wishes to update its charges or wishes to introduce new services over the PSTN, a protracted and difficult upgrading process can be required to enable the billing system to cater for the new charging regime.